The present invention relates to a shot gun cartridge, in particular for a shot gun with a rifled barrel, which cartridge has a sub-calibrated bullet accommodated in a thrust cage.
Cartridges having sub-calibered bullets with thrust cage, also called sabot, are increasingly preferred in particular for guns with an entirely or partially rifled barrel, due to the better shooting accuracy and greater target energy. Examples of cartridges with such bullets are found in the unexamined German patent application Nos. 24 44 181 and 17 03 119. After leaving the gun barrel, the thrust cage and bullet separate from each other and the latter continues its path to the target alone while the thrust cage falls to the ground after a short trajectory.
It is the task of the present invention to provide an innovation in a shot gun cartridge for use in a shot gun having a rifled barrel.
This task is solved by the provision of a shot gun cartridge having an enhanced sub-calibered bullet accommodated in a thrust cage which, in turn, is disposed in a cartridge case. The cartridge case is stationarily disposable in a shot gun and has a forward end locatable adjacent to an entry end of a rifled barrel of the shot gun. The thrust cage has a back end, an annular tubular body attached to and extending forwardly from the back end, and a front end on the annular tubular body defining a front opening. The thrust cage is disposed in the cartridge case with the front end of the thrust cage located adjacent to the forward end of the cartridge case. Also, thrust cage is movable relative to the cartridge case forwardly toward the entry end of the rifled barrel of the shot gun in response to a blast generated in the cartridge case rearwardly of and transmitted to the back end of the thrust gage. The enhanced sub-calibered bullet is disposed in the thrust cage and includes a shell jacket and a bullet core. The shell jacket is disposed in the annular tubular body of the thrust cage and has a front face disposed adjacent to the front end of the thrust cage, a rear face spaced forwardly of the back end of the thrust cage, respective forward and rearward portions connected together in a tandem arrangement with one another and extending between the front and rear faces of the shell jacket, and an axial bore defined through the shell jacket by the forward and rearward portions of the shell jacket and longitudinally extending between the front and rear faces of the shell jacket. The bore has a larger maximum cross-sectional size in the forward portion than in the rearward portion of the shell jacket and defines front and rear openings in the shell jacket at the front and rear faces thereof. The bullet core includes a front portion having a forwardly tapering configuration so as to provide a head extending forwardly through the bore in the forward portion of the shell jacket, a back portion larger in cross-sectional size than the front portion of the bullet core and the bore in the rearward portion of the shell jacket so as to provide a back plate, and an intermediate portion smaller in cross-sectional size than the bore in the forward and rearward portions of the shell jacket so as to provide a shaft extending through the rear opening of the shell jacket and between and interconnecting the head and back plate and adapted to guide slidable movement of the bullet core relative to the shell jacket from a pre-blast position providing an initial loaded form of the bullet, in which the shaft extends through and rearwardly of the rear opening of the shell jacket and supports the back plate at a location spaced rearwardly of the bore and the rear face of the shell jacket and adjacent the back end of the thrust cage with the head disposed substantially within the bore in the forward portion of the shell jacket and extending forwardly through the front openings of the shell jacket and thrust cage, to a post-blast position providing a final form of the bullet shot from the gun, in which the back plate is disposed rearwardly of the bore of the shell jacket and exteriorly of and flush against an abutment defined by the rear face of the shell jacket and the head projects forwardly of the front face of the shell jacket and the front opening therein, in response to the thrust cage being moved forwardly relative to the cartridge case in response to the blast generated in the cartridge case rearwardly of the back end of the thrust cage.
At the beginning of the generation of the blast the developing gas pressure thrusts the bullet core in the shell jacket forward up to the abutment and therewith establishes the final form of the bullet. Therewith, given the corresponding material selection for the bullet core and the shell jacket, the center of the mass is shifted toward the back which, when shooting from guns with an entirely or partially rifled barrel, ensures good shooting precision.
In the case of bullets it is customary, in view of the relatively progressive thrusting charge power used, to employ deformable intermediate means disposed between the bullet proper and the thrusting charge which are compressed during the starting gas pressure development whereby the combustion volume is enlarged and thus the gas pressure peak in reduced. Due to the displacement of the bullet core together with the thrust cage relative to the shell jacket which initially persists due to its inertia, the same effect is obtained in the bullet according to the invention. During assembling of the shell jacket and bullet core, depending on the shell volume available, these bullets can be used together with buffering or non-buffering intermediate means.
After the production of the final bullet form it must be ensured that the dynamic pressure of the air acting on the bullet trajectory does not push back the bullet core. It is understood that this can be realized by setting up a corresponding fit between the shell jacket and the bullet core such that the bullet core at the end of its displacement path is clamped in the shell jacket. This clamping effect can be attained, for example, by knurling of the bullet core which during a blast generation more or less strongly xe2x80x9ceats intoxe2x80x9d the inner wall of the shell jacket.
A bullet embodied according to the invention offers diverse feasibilities in order to attain a cross section enlargement desired in terms of target ballistics, and also referred to as mushrooming out, of the bullet during the penetration into a target medium. For example, a mushrooming-out formation of the shell jacket is already achieved through the bullet core crushing when impinging onto a target alone. A further improvement can be attained thereby that for the shell jacket a softer material, for example copper, than for the bullet core is selected, which can comprise, for example, steel. To control the mushrooming-out behavior of the shell jacket it is also possible to vary its wall thickness correspondingly, or nominal buckling sites can be provided.
Further influencing the cross section enlargement of the bullet can comprise that the inner surface of the shell jacket and the contour of the bullet core have corresponding outformings which through the impingement and the penetration of the target medium initiate a deformation of the bullet controlled with respect to form and extent.
It is furthermore feasible to structure the forward-side end of the shell jacket to be open or concealed. The former causes a more rapid initiation of the mushrooming-out. The concealed opening delays the deformation but, due to the better form value, has external ballistic advantages and a greater depth effect in the target. The one or the other embodiment can be employed depending on the application purpose.
But even in the nondeformed state, a bullet according to the invention, compared to the known sabot bullets in diabolo form, has a 60% greater bullet cross sectional area and is a match with their strongest propelling charge in terms of the impact energy at 100 m. Therefore a bullet according to the invention also yields comparatively good results in an assessment through the KO formula developed by Taylor.
In a further embodiment of the invention the point of the bullet head has essentially the form of a slender cone. This form is possible since in the loaded state the bullet head is largely sunk into the shell jacket. With the cartridge loaded, the point of the bullet head does thereby not project above the crimped shell mouth of the cartridge such that the cartridges can be loaded without hazard into weapons with tubular magazines.
In one embodiment of the invention the bullet head at the end of the displacement of the bullet core is in contact with its outer circumference on the inner circumference of the shell jacket; that means the forward-side end face of the bullet is closed with the cone-shaped point of the bullet head projecting over this front side. This development lends the bullet a ballistically favorable form. Its ballistic coefficient is now approximately 100% greater than that of conventional gun-barrel bullets with flat head or, at best, indicated small bullet point. This leads to the fact that, compared to those bullets of identical caliber and with performance values of approximately identical magnitude at the muzzle, at a shooting distance of approximately 100 m, a markedly higher impact energy, flatter trajectory and lesser side wind sensitivity are obtained. Of advantage is also the sharp edge formed by the forward-side face of the shell jacket, which yields a caliber-size entrance hole.
The under-calibered gun-barrel bullet according to the invention, compared to the known, so-called xe2x80x9csabotxe2x80x9d bullet, has the advantage of greater caliber (16 mm Ø in caliber 12) at approximately identical ballistic coefficient. It is conceived as a bullet free of harmful substances. Should for special requirements a bullet of lead be preferred, this can be realized without major problems. Fundamentally, a conversion to special suitable materials and/or application of special processing methods, such as, for example, hardening of the bullet core with modified form, permit the bullet to appear suitable for special application areas, such as for example, the government area.
The gun-barrel bullet according to the invention is conceived in particular for use in entirely or partially rifled gun barrels. Shooting from smooth gun barrels is not recommended. From rifled barrels, it yields up to the 100 m range a good shooting precision, high impact energy and high tendency for deformation. These are requirements made increasingly more frequently in recent times since in many countries the use of rifle cartridges when hunting is forbidden due to the large hazard region.